Basically, you edit /etc/grub.d/40_custom by copying/pasting one of the examples provided in post #1 (version name/ISO may be out of date), modify the entry according to your ISO location and partition layout, and then run update-grub .

But This needs to be changed depending on your configuration, Note the the harddrive information needs to be changed, so (hd0,1) which refers to /dev/sda1 0 being sda, and 1 being the partition, so for my partition I changed this to (hd0,3) because it is sda3. Also I notice where it says rescue64 this is actually the 64bit version name, so the code didn't work on my system that is 32bit, to solve this change that to rescuecd, and change all the .iso names to match your iso file, mine is called "sysrcd.iso" so that gives us the customized entry to match settings.

Once you change your file to run update-grub then reboot and key into grub to find your custom iso boot (note that this is grub 2). Big thanks to mikewhatever for finding that, exactally what I needed to get started. This will save me a stack of burning live disks.